This invention relates to communication with wireless tags and, more particularly to a method and system for communicating with multiple types of tags.
A tag is a wireless electronic device that communicates with a reader. Typically, tags consist of an integrated circuit and a coil. The coil acts as a source of power, as a receiving antenna, and a transmitting antenna. The integrated circuit includes wireless communications components, and at least some memory. The reader directs an electromagnetic (i.e. radio) signal to the tag, referred to as xe2x80x9cilluminatingxe2x80x9d the tag. For example, for some tags, the signal frequency is 125 KHz. A tag is tuned to the frequency broadcast by the reader, and receives power from the 125 KHz signal. Upon power-on, the tag performs certain operations, which generally include transmitting information and receiving instructions. Depending on the type of tag, the instructions can include data requests, or information to be stored in tag memory. The actions taken by a tag when the tag is illuminated, and the capabilities of the tag, are different for each tag type and model.
There are tags commercially available from companies such as EM Microelectronic-Marin SA of Marin, Switzerland (xe2x80x9cMarinxe2x80x9d), Philips Semiconductors of Sunnyvale, Calif. and Microchip Technology, Inc. of Chandler, Ariz. The various tags have some similar properties and some different properties. The different properties of the different tags often are not an operational barrier, since, generally, the same type of tags are used in a particular system implementation. However, in some implementations, a reader that only reads one type of tag can be unduly limited.
In general, in one aspect, the invention features a method for communicating with a RFID tag. The method includes receiving a signal from a RFID tag, and identifying the tag type from the RFID tag signal. In one embodiment, the method includes the step of parsing the signal as a start signal for the identified tag type. In another embodiment, the method includes the step of receiving Manchester encoded data. In another embodiment, the method includes the step of sending a data request to the tag based on the tag type. In another embodiment, the method includes the step of receiving information stored in the tag in response to the request. In another embodiment, the receiving step includes receiving a signal from the RFID tag and identifying the tag type from the RFID tag signal. In another embodiment, the receiving step includes parsing the start signal for the identified tag type and receiving Manchester encoded data comprising the information stored in the tag. In another embodiment, the method includes the step of communicating the received information to a computer. In another embodiment, the method includes the step of decoding the Manchester encoded data, and communicating the decoded data to a computer. In another embodiment, the method includes the step of communicating a receiver identifier to the computer.
In general, in another aspect, the invention features a method for communicating tag information that includes transmitting tag information from a tag receiver to a computer and transmitting a receiver identifier from the tag receiver to the computer.
In general, in another aspect, the invention features a system for communicating with a RFID tag that includes a receiver for receiving a signal from a RFID tag and an identification module for identifying the tag type from the RFID tag signal. In one embodiment, the identification module parses the signal as a start signal for the identified tag type. In another embodiment, the receiver receives Manchester encoded data. In another embodiment, the receiver sends a data request to the tag based on the tag type. In another embodiment, the receiver receives information stored in the tag in response to the request. In another embodiment, the information is received by the receiver receiving a signal from the RFID tag; and the identifier identifies the tag type from the RFID tag signal. In another embodiment, the information is received by the receiver by parsing the start signal for the identified tag type and then receiving Manchester encoded data comprising the information stored in the tag. In another embodiment, the system includes a transmitter communicating the received information to a computer. In another embodiment, the transmitter communicates the decoded Manchester encoded data to a computer. In another embodiment, the transmitter communicates a receiver identifier to the computer.
In general, in another aspect, the invention features a system for communicating tag information that includes a receiver identifier and a transmitter for transmitting tag information and the receiver identifier from a tag receiver to a computer. In one embodiment, the system also includes a computer receiving the tag information and the receiver identifier from the transmitter and communicating the tag information and the receiver identifier over a network.
The foregoing and other objects, aspects, features, and advantages of the invention will become more apparent from the following description and from the claims.